spring 初始化和销毁的三种方法

spring 中初始化和销毁有三种办法

1. 实现接口 DisposableBean ,initilzingBean
2. 使用注解 @PostConstructor, @PreDestory
3. xml 配置 init-methods, destory-method , 或者在 @Bean(initMethod = "",destroyMethod="")

代码如下
config 配置Bean

package com.shanjiancaofu.ad.service.impl;

import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;

@Configuration
public class AppConfig {
       // initMethod  指定类的初始化方法, destroyMethod 指定类的销毁方法
    @Bean(initMethod = "init", destroyMethod = "destroyMethod")
    User user() {
        return new User();
    }
}

User 类

package com.shanjiancaofu.ad.service.impl;

import org.springframework.beans.factory.DisposableBean;
import org.springframework.beans.factory.InitializingBean;

import javax.annotation.PostConstruct;
import javax.annotation.PreDestroy;


class User implements InitializingBean, DisposableBean {
    public String userName;

    public User() {
        System.out.println("User constructor");
    }

    public void init() {
        this.userName = "initName";
        System.out.println(" user init. ....");
    }

    public void destroyMethod() {
        this.userName = "destroyName";
        System.out.println(" user destroy. ....");
    }

    @PreDestroy
    public void preDestroy() {
        System.out.println("@PreDestroy ...");
    }

    @PostConstruct
    public void postConstruct() {
        System.out.println(" @PostConstruct. ....");
    }

    @Override
    public String toString() {
        return "user:" + this.userName;
    }

    @Override
    public void afterPropertiesSet() throws Exception {
        System.out.println("InitializingBean afterPropertiesSet");
    }

    @Override
    public void destroy() throws Exception {
        System.out.println("DisposableBean destroy");
    }
}

启动spring 应用 控制台输出:

User constructor
@PostConstruct. ....
InitializingBean afterPropertiesSet
user init. ....

关闭spring 应用 控制台输出:

@PreDestroy ...
DisposableBean destroy
user destroy. ....

和开头我们总结的顺序结论一致. 重要的是,类的构造器是最先执行的.

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